Fasciation Fascination

July 4, 2020

Image of a sotol plant
Caused by fasciation, a cluster of abnormal leaves instead of a tall flower stalk is growing from the center of this sotol plant. Photo credit J. Linnell


What is ailing this sotol plant, and can you suggest a remedy?

- J. Linnell, submitted via Bernalillo County Extension Agent Sara Moran


I see why you’re concerned about your sotol. In the center, where the 5- to 20-foot-tall flower stalk should be, there’s a squished-up clump of spiny stems that look like a pile of curly green lizard tails. I’ve never seen anything quite like this before, but it looks to me like it could be a type of fasciation.

Image of a desert willow branches in an open field
Stem fusion on desert willow branches in Tucumcari at NMSU’s Rex E. Kirksey Agricultural Science Center is a great example of fasciation in action. Photo credits M. Thompson

Fasciation is an abnormal growth condition that is usually associated with hormonal imbalances within specific plant tissues—often, and in this case, in the floral stem. Like animals, plants produce hormones that act as mobile chemical signals and control all kinds of physiological processes throughout the entire life of the plant.

Plant hormones (aka phytohormones or plant growth regulators) are involved in everything from the exact timing of seed germination and flowering to fruit ripening. Those events are also dependent on other external and internal cues, but the hormones produced in response to cues (like changes in temperature) become the triggers for whatever comes next, or doesn’t, in the life cycle.

Hormonal imbalances that lead to fasciation can be brought on in response to tissue damage by insects or other animals; bacterial, fungal, or viral infections; random genetic mutations; or other environmental stressors. I don’t know what would have caused the floral structure in the center of your sotol plant to develop into a nest of mutated leaves, but I don’t think there’s anything that can be done to fix it now. And I don’t think you could have done anything to prevent it either. I’ll be interested to see how these funny leaves grow, how your plant responds, and whether it all happens again next year.

Image of a mullein flower stalk near a mountain range
A fasciated mullein flower stalk at El Malpais National Monument in September 2017. Photo credits M. Thompson

Fasciation is more common in tissues in which cells are growing and dividing rapidly, so it makes sense that they result in floral mutations and also cool-looking fused stems. I can’t help but stop to take photos of fasciated plants when I see them. And I’m not the only one. I belong to a Facebook group with over 3,000 members called “Fasciation Fascination,” where people from all over the world share photos of these oddball plants—dozens of which were photographed right here in New Mexico.

For the fun of it, I searched the Fasciation Fascination page for other sotol photos, thinking maybe it’s more common than I thought. None came up. Sotols (Dasylirion species) are in the Asparagaceae family that includes yuccas, agaves, and asparagus (among others). So, I also searched for these close relatives. No yuccas have been reported so far, but I did find photos of extremely weird-looking flower stalks on two different twin-flowered agaves posted years apart. And there are multiple posts on fasciated asparagus. I reached out to the person with the most recent asparagus-gone-wild post, Lisa Temple-Cox in Essex England, to ask if I can publish her photos from June 14 in this week’s column. Not only did she happily grant me permission to use the photos, but she also shared updated photos showing how her fasciated asparagus plants have developed in the past few weeks, and one of them now has normal-looking baby asparagus stalks emerging from the top of a contorted fused stem!

Image of asparagus stalks
Pictures of fasciated asparagus stalks posted on June 14, 2020, on the Fasciation Fascination Facebook group page. Photo credits Lisa Temple-Cox

Marisa Y. Thompson, PhD, is the Extension Horticulture Specialist, in the Department of Extension Plant Sciences at the New Mexico State University Los Lunas Agricultural Science Center, email: desertblooms@nmsu.edu, office: 505-865-7340, ext. 113.


For more gardening information, visit the NMSU Extension Horticulture page at Desert Blooms and the NMSU Horticulture Publications page.

Send gardening questions to Southwest Yard and Garden - Attn: Dr. Marisa Thompson at desertblooms@nmsu.edu, or at the Desert Blooms Facebook page.

Please copy your County Extension Agent and indicate your county of residence when you submit your question!

Image of updated asparagus stalks
Updated photos of fasciated asparagus stalks posted on June 23, 2020, on the Fasciation Fascination Facebook group page. Photo credits Lisa Temple-Cox